Urgent Request for Approval of PG&E's Temporary Variance of Flow Requirements

Strategic Insights -

California Trout, Inc., along with Friends of the Eel River and Trout Unlimited, have submitted a document to the Federal Energy Regulatory Commission requesting the immediate approval of Pacific Gas and Electric Company's (PG&E) application for a temporary variance of flow requirements for the Potter Valley Project. The request is made to protect imperiled salmonid species in the Eel River, as the significant and worsening limitations on storage capacity in Lake Pillsbury render the current flow schedule unachievable in most years.

Key Takeaways:

  • The Potter Valley Project's ability to meet prescribed flows is severely constrained due to the need to retain 12,000 acre-feet to avoid sediment blockage of the only functioning low-level outlet.
  • PG&E's current request seeks authorization for a targeted and flexible flow management strategy to proactively manage Lake Pillsbury's cold-water pool, essential to the survival of ESA-listed juvenile steelhead downstream of Scott Dam.
  • The company's request aligns with interim protective measures proposed by the National Marine Fisheries Service (NMFS), which have been endorsed by the California Department of Fish and Wildlife (CDFW) and adopted by the Commission in previous years.
  • Delays in approving previous variances have had serious consequences, including elevated release temperatures that pushed conditions near the lethal threshold for rearing juvenile steelhead.
  • PG&E's proposed 2025 variance is not a new concept but builds upon a proven framework used in past years and already analyzed and supported by FERC, NMFS, and CDFW.
  • The 2025 temporary variance represents a science-based, flexible effort to mitigate impacts while maintaining public safety and water supply reliability.
  • A prompt decision by the Commission will enable immediate changes to reservoir operations that preserve cold-water storage through the critical summer months and provide desperately needed protections for the Eel River's recovering fisheries.

Statistics:

  • 20,000 acre-feet: The effective storage volume eliminated by the California Division of Safety of Dams (DSOD) requiring PG&E to keep the spillway gates at Scott Dam permanently open.
  • 12,000 acre-feet: The storage volume needed to avoid sediment blockage of the only functioning low-level outlet.
  • 22.6degC: The highest release temperature from the Potter Valley Project in 2023, which contributed to catastrophic losses for juvenile steelhead.
  • June: The month when daily average water temperatures often exceed 15degC, necessitating the reduction of outflow from Lake Pillsbury to protect its cold-water pool.

Sources:

  • Letter to Debbie-Anne Reese, Acting Secretary Federal Energy Regulatory Commission, from Redgie Collins, Legal and Policy Director, California Trout, et al. (May 15, 2025)
  • Pacific Gas and Electric Company's application for a temporary variance of flow requirements for the Potter Valley Project (FERC Project No. 77)
  • National Marine Fisheries Service letter to FERC, Endangered Species Act and Magnuson-Stevens Fishery Conservation and Management Act Consultations on the Potter Valley Project (P-77) on the Eel River, California (March 16, 2022)
  • California Data Exchange Center reporting for Potter Valley Project (PG2) at https://cdec.water.ca.gov/dynamicapp/queryGroup?s=pg2&dur_code=D